1. Field of the Invention
Aspects of the present invention relate to a fusing unit and an image forming apparatus including the same, and more particularly, to a fusing unit that has improved durability, and an image forming apparatus including the same.
2. Description of the Related Art
An electrophotographic image forming apparatus forms an image on a printing medium through charging-exposing-developing-transferring-fusing-cleaning processes. Exemplary electrophotographic image forming apparatuses include a laser printer, a photocopier, a facsimile machine, a multifunctional device, etc. An electrophotographic image forming apparatus includes a fusing unit which performs the fusing process. The fusing unit fuses a visible image formed of a developer to a printing medium, with heat and pressure.
The fusing unit includes a heated body, a heating member, which heats the heated body, and a pressure member, which presses the printing medium to the heated body. The fusing unit may be classified into a belt-type or a roller-type, depending on the type of the heated body.
The belt-type fusing unit may be classified into a tension belt-type or a non-tension belt-type. The non-tension belt-type fusing unit is popular, since it loses less heat and reduces material costs, as compared to the tension belt-type fusing unit, which includes two belt driving rollers.
The non-tension belt-type fusing unit includes two end-supporting members, to rotatably support opposite ends of the belt in a transverse direction, with respect to a rotation direction of the belt. A lubricant is applied to surfaces of the end supporting members, which contact the belt, such that the belt smoothly rotates, and to reduce wear of the belt, due to the friction. However, as the belt rotates, the lubricant leaks, and moves out of the contact surfaces. Then, the belt may be worn and/or damaged by the friction with the end supporting members.
To address the foregoing problem, Japanese Patent First Publication No. 2006-227106 suggests installing a sealing ring on surfaces of the end supporting members, which contact the belt, to prevent the lubricant from leaking. However, the foregoing apparatus does not prevent the lubricant from leaking to an opposite side, which does not have the sealing ring. If the number of the sealing rings increases, the lubricant is stuck between the sealing rings, and is less effective in lubricating the contact surfaces. Moreover, the lubricant continues to leak from the side that does not have the sealing ring. Thus, there are limitations in preventing the lubricant leakage, using only the sealing rings.